Epidemiological inferences and observations in humans point to the possible significance of dietary bran in inhibiting colon cancer in humans. In spite of this, no studies have been performed using well characterized dietary bran to determine its effect on colon cancer induced in animals. This suggests the need for studies to carefully determine the relative effectiveness of various forms of dietary bran in inhibiting colon cancer using animal models. The objective of the proposed research is to determine the relative effectiveness of four forms of well characterized dietary bran, (a) corn bran, (b) soybean bran, (c) wheat bran from soft winter wheat, in inhibiting colon carcinogenesis in 1,2-dimethylhydrazine(DMH) treated BALB/c mice. BALB/c mice will be fed pelleted diets containing 20% bran beginning at 8 weeks of age; DMH will be injected S.C. at a rate of 20 mg/kg body weight weekly for 10 weeks beginning at 11 weeks of age following our previously described treatment regime. Mice will be held for approximately 40 weeks following initial injections at which time they will be killed. The evaluation of the relative effectiveness of these dietary brans in inhibiting colon carcinogenesis will then be made in terms of (a) tumor incidence, (b) numbers of tumors per tumor bearing mouse, and (c) classification and multiplicity of tumors per mouse. These experiments should provide information regarding the possible role of dietary bran and which type(s) of bran are most effective in modifying DMH-tumorigenesis as well as suggesting which might be of benefit prophylactically or therapeutically in humans.